This research project will develop a new method to study short-lived complexes in solution. The study of nuclear relaxation times, arising from the coupling of solvent molecules with paramagnetic solutes will provide detailed information about the dynamics of intermolecular interactions on the 10 to the minus 8th power to 10 to the minus 11th power second time scale. At present no method exists by which such short-lived interactions can be examined directly. Initially, the experimental program has involved developing the instrumentation capable of measurement of fast nuclear relaxation times at multiple field strengths and testing the mathematical model used to describe the complexation. Future work will examine the dynamics and mechanisms of simple nitroxide interactions with water and benzene, apply the method to studies of hydrogen bonding in solution, and investigate in detail the variables that determine the strength and lifetime of labile complexes. The goal is to determine the rates of forming and breaking these bonds between solvent and solute, and to isolate the parameters that bring about changes in bonding strength and dynamics. Interactions such hydrogen bonding are extremely significant in physical chemistry and health related sciences becauses they determine the nature of liquids in general and the specific properties of systems under investigation.